Incandescent electric lamp



A. R DENNINGTON.

INCANDESCENT ELECTRIC LAMP.

APPLICATION FILED APR. 12, HHS.

1,319,853. Patented Oct. 28,1919.

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I I A'i'TORNEY UNITED STATES PATENT OFFICE.-

ARTHUR R. DENNINGTON, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTING- HOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

INCANDESCEN'I ELECTRIC LAMP.

Specification of Letters Patent.

Patented Oct. 28, 1919.

Application filed April 12, 1916. Serial No. 90,711.

'To all whom it may concern Be it known that I, ARTHUR H, DENNING- TON, a citizen of the United States, and a resident of East Orange, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Incandescent Electric Lamps, of which the following is a specification.

My invention relates to incandescent electric lamps and it has special relation to lamps which are adapted for series operation and which are commonly provided with cutouts for" restoring the continuity of the circuit when the lamp is burned out in service.

The object of my invention is to provide a cutout device for incandescent electric lamps of the above indicated character which shall be simple and inexpensive in construction and entirely reliable and positive in operation.

In the accompanying drawing, Figure 1 is a side elevational View, with parts in section, showing an incandescent lamp of the street series type provided with a film cutout constructed in accordance with my invention, and Fig. :2 is a side elevational view of a portion of the structure shown in Fig 1, illustrating a modified forlnof cutout.

In most of its structural details, the lamp shown herein conforms to a well-known type of street series incandescent lamp. It consists of a bulb 1 inclosing a concentrated metallic filament 2 which is supported upon leading-in wires 3 and 4. The leading-in wires extend through the press 5 ot' a tubular stem 6 which is sealed to the bulb 1 within a terminal cap 7.

Disposed within the .hollow tubular portion of-the stem 6, as shown in Fig. 1, is a helical spring 8, the convolutions of which are in electrical contact with the leading-in wire 3, but are separated from the leadingin wire 4 by an insulating film 9 which may conveniently consist of a strip ofoiled paper, cloth or other thin insulating material.

In the modified form of device shown in Fig. 2, the spring within the stem consists of one or more loops 11 of zigzag construction. Numerous other forms of springs may be utilized for my present purpose. but whatever maybe the particular form se lccted, I prefer that a number of possible points of contact shall be provided in order to insure that the device will operate properly.

When a burnout or other failure of the filament occurs in a lamp of the type which to form a good conducting path between the leading-in wires, and an arc may thus be formed between the leading-in wires when the filament burns out. In such a case, the arc travels along the leading-in wires to the stem, and the heat conducted from the are through the leading-in wires is sufficient to burn the insulating film and cause the cutout spring to connect the leading-in wires and short-circuit the lamp.

By providing several possible points of contact betweenthe leading-in wires, I effectually prevent the possibility of arcing between the leading-in wires at points intermediate the cutout. device and the lamp base. The base and the socket are thereby fully protected from damage, and positive maintenance of the circuit is insured.

I have shown and described a form of device which I have found to be well suited for the purposes specified, but it is not to be understood that my invention is restricted to the structural details of these devices or that any other limitations are to be imposed upon my invention except such as are indicated in the appended claims.

I claim as my invention:

1. An incandescent electric lamp comprising a filament, leading-in wires therefor and afilm cutout disposed between the said leading-in wires and comprising a spring contact member having a plurality of convolutions which engage one of the said leading-in wires and are separated from the other leading-in wire by an insulating film.

2. An incandescent electric. lamp comprising a filament, leading-in wires therefor, and a film cutout disposed between the said leading-in wires and comprisinga helical spring contact member having a plurality of its convolutions in electrical cmtact with one of the said leading-in wires having a plurality of convolutions which and separated from the other leading-in engage one of the said leading-in Wires and 10 Wire by an insulating film, are separated from the other leading-in 3. An incandescent electric lamp com- Wires by an insulating film. prising a filament, leading-in Wires there- In testimony whereof, I have hereunto for, a tubular stem inclosing portions of the subscribed my name this twenty-seventh said leading-in wires, and a spring contact day of March, 1916. member disposed within the said stem and ARTHUR 'R. DENNINQTON. 

